The questions are all answered in the technical data sheets for the products purchased.
Google search criteria "spraymax technical data sheet"
Example:
Scroll down and look for "technical information sheets"
https://www.spraymax.com/en-us/products/product/primer-primer-filler/2k-epoxy-primer-1/Repeat same process for all products. Read and understand the material before jumping in.
They seem aware their products are geared towards non-professionals so the data sheets are better written and more complete than average.
Do not screw around with safety using any of the 2k products: Wear a real respirator approved for organic vapor, not just a dust mask.
Gloves are a good idea as well.
Your overall plan sounds good but as others state, sand tends to get lodged between the center and the rim. Might want to at least pick it out.
Not every one agrees but I spray nothing on bare metal without wax and grease remover. If solvent borne wait 1/2 hour or more for evap.
If Waterborne or something to like Sprayway glass cleaner, a few minutes after wipe off is usually adequate.
*lengthen the time for high humidity conditions
I'd also want a tack cloth........Always tack off before clear, at a bare minimum, to try to avoid visible chunks below the clear. Once something is buried under the clear, it's not going anywhere....
Not everyone would agree.....
